[PATCH 3/5] ntoskrnl.exe: Implement PsIsSystemThread.

[Derek Lesho]

Signed-off-by: Derek Lesho 
---
 dlls/ntoskrnl.exe/ntoskrnl.c        | 23 +++++++++++++++++++++++
 dlls/ntoskrnl.exe/ntoskrnl.exe.spec |  2 +-
 dlls/ntoskrnl.exe/tests/driver.c    | 19 +++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/dlls/ntoskrnl.exe/ntoskrnl.c b/dlls/ntoskrnl.exe/ntoskrnl.c
index 61a3e4ba92..335918f99f 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.c
+++ b/dlls/ntoskrnl.exe/ntoskrnl.c
@@ -2987,6 +2987,29 @@ HANDLE WINAPI PsGetCurrentThreadId(void)
 }

+/***********************************************************************
+ *           PsIsSystemThread   (NTOSKRNL.EXE.@)
+ */
+BOOLEAN WINAPI PsIsSystemThread(PETHREAD thread)
+{
+    HANDLE hThread;
+    DWORD tid = 0;
+
+    if (!thread)
+        return TRUE;
+
+    /* get handle, then id */
+    if ((hThread = kernel_object_handle( thread, THREAD_ALL_ACCESS )))
+    {
+        tid = GetProcessId( hThread );
+        NtClose(hThread);
+    }
+
+    /* Should only show up as client_tid but request_thread is added for redundancy */
+    return tid != client_tid && tid != request_thread;
+}
+
+
 /***********************************************************************
  *           PsGetVersion   (NTOSKRNL.EXE.@)
  */
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 43f47470a9..0e9e6a7630 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -907,7 +907,7 @@
 @ stdcall PsImpersonateClient(ptr ptr long long long)
 @ stub PsInitialSystemProcess
 @ stub PsIsProcessBeingDebugged
-@ stub PsIsSystemThread
+@ stdcall PsIsSystemThread(ptr)
 @ stub PsIsThreadImpersonating
 @ stub PsIsThreadTerminating
 @ stub PsJobType
diff --git a/dlls/ntoskrnl.exe/tests/driver.c b/dlls/ntoskrnl.exe/tests/driver.c
index 88237461d5..c436f2c3d9 100644
--- a/dlls/ntoskrnl.exe/tests/driver.c
+++ b/dlls/ntoskrnl.exe/tests/driver.c
@@ -814,6 +814,24 @@ static void test_ob_reference(const WCHAR *test_path)
     ok(!status, "ZwClose failed: %#x\n", status);
 }

+static void WINAPI system_thread( void *arg )
+{
+    BOOLEAN result;
+
+    ok((result = PsIsSystemThread()), "got %u\n", result);
+
+    PsTerminateSystemThread( STATUS_SUCCESS );
+}
+
+static void test_system_thread()
+{
+    BOOLEAN result;
+
+    ok(!(result = PsIsSystemThread()), "got %u\n", result);
+
+    run_thread( system_thread, (void*)0 );
+}
+
 static NTSTATUS main_test(DEVICE_OBJECT *device, IRP *irp, IO_STACK_LOCATION *stack, ULONG_PTR *info)
 {
     ULONG length = stack->Parameters.DeviceIoControl.OutputBufferLength;
@@ -856,6 +874,7 @@ static NTSTATUS main_test(DEVICE_OBJECT *device, IRP *irp, IO_STACK_LOCATION *st
     test_stack_callout();
     test_lookaside_list();
     test_ob_reference(test_input->path);
+    test_system_thread();

/* print process report */
     if (winetest_debug)